Nissan Frontier. Manual - part 431

P0448 EVAP CANISTER VENT CONTROL VALVE

EC-295

< DTC/CIRCUIT DIAGNOSIS >

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If 1st trip DTC is not detected, go to the next step.

7. Repeat next procedure 20 times.
a. Quickly increase the engine speed between 4,000 and 4,500 rpm and maintain that speed for 25 to 30

seconds.

b. Fully released accelerator pedal and keep engine idle for at least 35 seconds.

8. Check 1st trip DTC.
9. If 1st trip DTC is detected, go to 

EC-295, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009480957

1.

CHECK RUBBER TUBE

1. Turn ignition switch OFF.

2. Disconnect rubber tube connected to EVAP canister vent control

valve (1).

- EVAP control system pressure sensor (2)

- Drain filter (3)

- EVAP canister (4)
- 

: Vehicle front

3. Check the rubber tube for clogging.
OK or NG

OK

>> GO TO 2.

NG

>> Clean rubber tube using an air blower.

2.

CHECK EVAP CANISTER VENT CONTROL VALVE

Refer to 

EC-296, "Component Inspection"

.

OK or NG

OK

>> GO TO 3.

NG

>> Replace EVAP canister vent control valve. Refer to 

FL-14, "Removal and Installation"

.

3.

CHECK IF EVAP CANISTER IS SATURATED WITH WATER

1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor

attached.

2. Does water drain from the EVAP canister?
Yes or No

Yes

>> GO TO 4.

No

>> GO TO 6.

JMBIA1516GB

ALBIA0514ZZ

BBIA0558E

EC-296

< DTC/CIRCUIT DIAGNOSIS >

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P0448 EVAP CANISTER VENT CONTROL VALVE

4.

CHECK EVAP CANISTER

Weigh the EVAP canister with the EVAP canister vent control valve and EVAP control system pressure sensor

attached.

The weight should be less than 2.0 kg (4.4 lb).
OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5.

DETECT MALFUNCTIONING PART

Check the following.

• EVAP canister for damage

• EVAP hose between EVAP canister and vehicle frame for clogging or poor connection

>> Repair hose or replace EVAP canister.

6.

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR

1. Disconnect EVAP control system pressure sensor (2) harness

connector.

- EVAP canister vent control valve (1)

- Drain filter (3)

- EVAP canister (4)
- 

: Vehicle front

2. Check that water is not inside connectors.
OK or NG

OK

>> GO TO 7.

NG

>> Replace EVAP control system pressure sensor. Refer to

FL-14, "Removal and Installation"

.

7.

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Refer to 

EC-309, "Component Inspection"

.

OK or NG

OK

>> GO TO 8.

NG

>> Replace EVAP control system pressure sensor. Refer to 

FL-14, "Removal and Installation"

.

8.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009480958

EVAP CANISTER VENT CONTROL VALVE

 With CONSULT

1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being

rusted.

If NG, replace EVAP canister vent control valve.

If OK, go to next step.

3. Reconnect harness connectors disconnected.
4. Turn ignition switch ON.

ALBIA0514ZZ

PBIB1033E

P0448 EVAP CANISTER VENT CONTROL VALVE

EC-297

< DTC/CIRCUIT DIAGNOSIS >

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5. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
6. Check air passage continuity and operation delay time.

Operation takes less than 1 second.

Make sure new O-ring is installed properly.

If NG, replace EVAP canister vent control valve.

If OK, go to next step.

7. Clean the air passage (Portion A to B) of EVAP canister vent control valve using an air blower.
8. Perform step 6 again.

 Without CONSULT

1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being

rusted.

3. Check air passage continuity and operation delay time under the

following conditions.

Operation takes less than 1 second.

Make sure new O-ring is installed properly.

If NG, replace EVAP canister vent control valve.

If OK, go to next step.

4. Clean the air passage (Portion A to B) of EVAP canister vent control valve using an air blower.
5. Perform step 3 again.

Condition VENT CONTROL/V

Air passage continuity between A and B

ON

No

OFF

Yes

PBIB1033E

Condition

Air passage continuity between A and B

12V direct current supply between
 terminals 1 and 2

No

OFF

Yes

PBIB1034E

EC-298

< DTC/CIRCUIT DIAGNOSIS >

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P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR

Component Description

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The EVAP control system pressure sensor (2) detects pressure in

the purge line. The sensor output voltage to the ECM increases as

pressure increases.

• EVAP canister vent control valve (1)

• Drain filter (3)

• EVAP canister (4)
•

: Vehicle front

On Board Diagnosis Logic

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NOTE:

If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to

EC-350

.

DTC Confirmation Procedure

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DTC CONFIRMATION PROCEDURE

NOTE:

Never remove fuel filler cap during DTC confirmation procedure.

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next test. 

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

With CONSULT>>GO TO 2.

Without CONSULT>>GO TO 5.

2.

PERFORM DTC CONFIRMATION PROCEDURE-1

With CONSULT

1. Start engine and let it idle for least 40 seconds.

NOTE:

Do not depress accelerator pedal even slightly.

2. Check 1st trip DTC.
Is 1st trip DTC detected?

ALBIA0514ZZ

PBIB3370E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0451
0451

EVAP control system pressure 
sensor performance

ECM detects a sloshing signal from the 
EVAP control system pressure sensor

• Harness or connectors
• EVAP control system pressure sensor